The present invention relates to a system for distributing road surface information, a system for collecting and distributing vehicle information and a device for transmitting vehicle information, and a program for controlling a vehicle. More particularly, the present invention relates to a system for distributing road surface information, a system for collecting and distributing vehicle information and a device for transmitting vehicle information, and a program for controlling a vehicle by which performance of the driving control of a vehicle can be improved on the basis of information on slipperiness such as a friction coefficient of the road surface where the vehicle travels.
When a vehicle suddenly accelerates or stops on a slippery road, there is a risk that the tires slip and spin. By sudden movements of the steering wheel, there is a possibility that the vehicle skids or spins.
Conventionally, there have been proposed techniques such as an antilock braking system (ABS) for reducing a brake torque acting on wheels to prevent the wheels from being locked before a damping force between tires and a road exceeds the maximum value and the tires are locked, thereby controlling the rotational speed of the wheels at which the maximum damping force can be obtained (Japanese Unexamined Patent Publication Nos. 99757/1985 and 249559/1989 and the like.)
For example, in the control of the antilock braking system, a slip ratio is calculated from a judged vehicle speed and a detected wheel speed (rotational speed) and, after that, a braking force is controlled so that the calculated slip ration coincides with a preset reference slip ratio. In such a manner, the maximum damping force is followed.
In the control of such an ABS or the like, a friction coefficient xcexc on a road is used, and the friction coefficient xcexc of the road surface during the travelling is calculated, and the data is used for the purpose of controlling its own vehicle.
However, the friction coefficient sensed by the travelling vehicle is a data which relates to the road surface of the part where the vehicle has already traveled, and the friction coefficient of the road surface where the vehicle will travel from now is required in controlling the vehicle.
For example, it is considered that, if data on the friction coefficient of a vehicle which is travelling ahead or a vehicle which has already traveled can be utilized by a vehicle which will travel from now, a more ideal vehicle movement control can be carried out.
In view of the aforementioned circumstances, an object of the present invention is to provide a system for distributing road surface information, a system for collecting and distributing vehicle information and a device for transmitting vehicle information, and a program for controlling a vehicle by which the efficiency of the driving control of a vehicle can be improved on the basis of information on slipperiness such as a friction coefficient of the road surface where the vehicle travels.
In accordance with the present invention, there is provided a system for distributing road surface information comprising means for sensing numerical information on slipperiness of a road surface while a vehicle is travelling; means for sensing positional information of the travelling vehicle; means for transmitting the numerical information and/or positional information from the vehicle; means for collecting the information transmitted by a plurality of vehicles; means for preparing road surface information of a road on the basis of each information; means for distributing the road surface information also to a vehicle other than the vehicle; and means for receiving the distributed road surface information.
In accordance with the present invention, there is also provided a system for collecting and distributing vehicle information characterized by collecting information which is transmitted from a travelling vehicle and needed in preparing road surface information, and distributing the road surface information also to a vehicle other than the vehicle.
In accordance with the present invention, there is further provided a device for transmitting vehicle information comprising means for sensing numerical information on slipperiness of a road surface while a vehicle is travelling; means for sensing positional information of the travelling vehicle; and means for transmitting the numerical information and/or positional information from the vehicle.
In accordance with the present invention, there is still further provided a program for controlling a vehicle characterized by allowing a computer to function as means for sensing numerical information on slipperiness of a road surface while the vehicle is travelling, means for controlling the vehicle on the basis of numerical information on slipperiness of a road surface received by the vehicle, and means for correcting the received numerical information on the slipperiness of the road surface by comparing the numerical information on the slipperiness of the road surface received by the vehicle with the numerical information on a road surface friction coefficient sensed during the travel, for improving performance of driving control of the vehicle on the basis of the road surface information.